From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Dan Carpenter , Stephen Rothwell , Keith Busch , "Michael S. Tsirkin" , Kees Cook , YueHaibing , Andrew Morton , Linus Torvalds , Sasha Levin , linux-mm@kvack.org Subject: [PATCH AUTOSEL 4.18 16/39] mm/gup_benchmark.c: prevent integer overflow in ioctl Date: Tue, 13 Nov 2018 00:50:30 -0500 Message-Id: <20181113055053.78352-16-sashal@kernel.org> In-Reply-To: <20181113055053.78352-1-sashal@kernel.org> References: <20181113055053.78352-1-sashal@kernel.org> List-ID: From: Dan Carpenter [ Upstream commit 4b408c74ee5a0b74fc9265c2fe39b0e7dec7c056 ] The concern here is that "gup->size" is a u64 and "nr_pages" is unsigned long. On 32 bit systems we could trick the kernel into allocating fewer pages than expected. Link: http://lkml.kernel.org/r/20181025061546.hnhkv33diogf2uis@kili.mountain Fixes: 64c349f4ae78 ("mm: add infrastructure for get_user_pages_fast() benchmarking") Signed-off-by: Dan Carpenter Acked-by: Kirill A. Shutemov Reviewed-by: Andrew Morton Cc: Stephen Rothwell Cc: Keith Busch Cc: "Michael S. Tsirkin" Cc: Kees Cook Cc: YueHaibing Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- mm/gup_benchmark.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c index 7405c9d89d65..7e6f2d2dafb5 100644 --- a/mm/gup_benchmark.c +++ b/mm/gup_benchmark.c @@ -23,6 +23,9 @@ static int __gup_benchmark_ioctl(unsigned int cmd, int nr; struct page **pages; + if (gup->size > ULONG_MAX) + return -EINVAL; + nr_pages = gup->size / PAGE_SIZE; pages = kvcalloc(nr_pages, sizeof(void *), GFP_KERNEL); if (!pages) -- 2.17.1